Area Forecast Discussion
Issued by NWS Marquette, MI
Issued by NWS Marquette, MI
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993 FXUS63 KMQT 211150 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 750 AM EDT Sat Sep 21 2024 .KEY MESSAGES... - Patchy fog possible early this morning, mainly central and east. - The prolonged stretch of above normal temperatures ends today, cooler temperatures near normal return on Sunday. - A round of showers and storms accompany a cold front tonight through Sunday. Severe weather is not anticipated, but some small hail and gusty winds are possible with stronger storms. && .SHORT TERM /TODAY/... Issued at 450 AM EDT Sat Sep 21 2024 Water vapor imagery/surface analysis early this morning has Upper Michigan under an area of subsidence in association with shortwave ridging behind yesterday`s cold front. So, clear skies for the majority of the day will result in one last day of above normal temperatures before a cooldown begins tomorrow. Therefore, trended close to guidance with highs topping off in the upper 70s/low 80s over much of the interior and even possible mid 80s over southerly downslope areas. The sun/clear skies will be short-lived, however, as the next low quickly pushes into eastern Manitoba/western Ontario through the course of the day. As a result, an uptick in cloud cover will commence over western Upper Michigan by late afternoon along with increasing shower/thunderstorm chances after Sat 20Z. Like yesterday, severe weather is not expected. But, small hail and brief, heavy downpours cannot be ruled out in some of the pop up activity. && .LONG TERM /TONIGHT THROUGH FRIDAY/... Issued at 435 AM EDT Sat Sep 21 2024 The extended forecast starts off with a ~1004mb sfc low north of the MN arrow head tonight which lifts northeast through Sunday toward Hudson Bay. This brings a cold front eastward across the UP and a round of showers and storms with it. Although bulk 0-6km wind shear will be ~35-40 kts with mid level lapse rates ~7C/km, instability is expected to be limited; likely less than 500 j/kg of MUCAPE. So severe weather is not anticipated, but some sub severe hail and gusty winds could accompany stronger storms earlier on tonight. CAMs are not in great agreement for arrival and placement of these showers and storms over the west half this evening/early tonight, but consistency increases early Sunday morning. At that point, there is higher confidence in a line of showers and storms over central Upper MI. This line gradually progresses eastward on Sunday with the cold front; dry weather returns to the entire CWA by midnight. Precip totals or this system look to be around a few hundreths to 0.25". Some northwest gusts up to 20-25 mph are likely on Sunday. Otherwise, lows tonight will be in the 50s, warmer in the east. Behind the cold front highs on Sunday will feel cooler, peaking in the low to mid 60s. For next week, quiet and dry weather likely returns for the first half. Some shortwaves riding northeast from the Central Plains through the southern half of the Great Lakes Basin Monday and Tuesday bring a weak sfc low along a similar path. Most guidance keeps best forcing and all precip south of our CWA save for the GFS which just scrapes the south and eastern portions of our CWA. Also, model soundings leave much to desire for available moisture and ensemble guidance only shows ~10-20% chances for at least a trace of precip, so opted for dry weather to start the work week. With clearing skies Sunday night and mostly clear skies likely for Monday might, some interior temps could get a bit cold, dropping into the 30s. Should these temps verify, some patchy frost could develop. Model guidance begins to diverge for the latter part of the work week, struggling to resolve the eastward progressing mid level trough over the northern portions of the CONUS. What could further complicate things are tropical systems in the Gulf of Mexico. General consensus is for the mid level ridge in the western CONUS Tuesday night and Wednesday to shift east, passing over the Great Lakes region for late next week and into the weekend. This would favor drier weather and eventually a return to above normal temps. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 748 AM EDT Sat Sep 21 2024 MVFR visibility restrictions should taper off over the next few hours at IWD, then becoming VFR. Elsewhere, VFR will be the prevailing flight category at CMX and SAW as well for most of the TAF period. The exception will be MVFR conditions at SAW early Sunday morning as a cold front brings rain showers. These rain showers will start at IWD first this afternoon, then progress eastward across Upper Michigan through Sunday morning. Also, cannot rule out some embedded thunder with the rain, but confidence is not high enough to insert mention at this time. Meanwhile, winds will remain below 12 kts, but there will be a gradual wind shift from the south to northwest with frontal passage through the course of the TAF period. && .MARINE... Issued at 435 AM EDT Sat Sep 21 2024 Light and somewhat variable winds today remain below 20 kts through early this evening as weak ridging briefly returns. Southerly winds increase up to 20 kts ahead of a cold front tonight. As this cold front passes eastward across the lake, winds winds quickly veer northwest gusting to 25 kts tonight through much of Sunday. There is a low chance (~30%) for gusts up to 30 kts early on tonight west of Isle Royale. Northwest winds veer north Sunday night, falling below 20 kts across the lake from west to east by Monday morning. This stronger period of northerly winds will result in wave heights building up to 4 ft along the western shores of the UP tonight as well as 4-6 ft over the east half of the lake late tonight through Sunday evening. Thunderstorms are possible with this front, but are not expected to be severe. Otherwise, winds are expected to remain below 20 kts the remainder of the forecast period. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...TDUD LONG TERM...Jablonski AVIATION...TDUD MARINE...Jablonski